Camshafts are an integral part of internal combustion engines. The camshaft comprises an (idle) shaft onto which at least one cam is joined. For joining the shaft and the cam, normally, thermal joining process are used. Here, the connection of the shaft and the cam is ensured via a joint surface of the cam, which normally is arranged in a cam bore, and a joint surface of the shaft. The advantage here is that the torque that can be transmitted via the camshaft is limited by the friction between the joint surface of the cam and the joint surface of the shaft.
From DE 10 2009 060 352 A1, a method is known for producing a camshaft for valve timing of an internal combustion engine, comprising the following steps: Aligning a plurality of disc-like cams, each having a central round opening extending perpendicular to a cam main plane in such a manner that the openings of the cams arranged axially spaced apart from each other are aligned with each other; undercooling an idle shaft having a round outer profile relative to the cam, wherein the outer diameter of the undercooled idle shaft is smaller than, and the outer diameter of the non-undercooled idle shaft is larger than, the inner diameter of the cam openings; inserting the undercooled idle shaft into the aligned cam openings; inducing a temperature equalization between the idle shaft and the cam so that the idle shaft and the cams are fixedly connected to form a camshaft, wherein the inner surfaces of the cam openings and/or the outer surface of the idle shaft, in their inserted state, have a rough pattern on the portions surrounded by the cam opening, which rough pattern is generated by means of laser ablation.